1. Field of the Invention
The present invention relates to an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus each having the electrophotographic photosensitive member, and an imide compound.
2. Description of the Related Art
An electrophotographic photosensitive member containing an organic photoconductive material (charge generating material) is mainly used as an electrophotographic photosensitive member mounted on a process cartridge and an electrophotographic apparatus. The electrophotographic photosensitive member generally has a support and a photosensitive layer formed on the support. Further, an undercoat layer is formed between the support and the photosensitive layer in many cases.
In recent years, the requirement to the quality of an electrophotographic image has been steadily increasing. For example, the tolerance to positive ghosting has been becoming remarkably severe. The positive ghosting is a phenomenon in which the density of only the portion irradiated with light becomes deep, when the portion irradiated with light is a halftone image at the next rotation of the electrophotographic photosensitive member while forming one sheet of the image.
A technique of allowing an electron transport material to be contained in an undercoat layer is known as a technique of suppressing (reducing) such a ghosting phenomenon.
As a technique of allowing an electron transport material to be contained in an undercoat layer, for example, Japanese Patent Application Laid-Open No. 2001-83726 and Japanese Patent Application Laid-Open No. 2003-345044 disclose a technique of allowing an electron transport material such as a fluorenone compound derivative and an imide compound derivative to be contained in an undercoat layer.
As a result of investigations by the inventors, it has been found that the prior art still has room for improvement with respect to the suppression (reduction) of the positive ghosting, particularly the variation (deterioration) of the positive ghosting level before and after continuous image output.